Pneumatic torque machine



March 30, 1948. c. BROECKER PNEUMATIC TORQUE MACHINE 4 Sheets-Sheet 1Original Filed Feb. 19, 1945 INVENTOR.

BY E i ATTORNEXS.

, 1943 4 Sheets-Sheet 2 VIIIIIIIIIIIIII. 4'1

Original Filed Feb. 19

O T r E V W g ii W WW II III] HII Ill HIIHIIIIIII IHHIHIIII III II March30, 1948. c. BROECKER 2,438,692

PNEUMATIC TORQUE MACHINE Original Filed Fb. 19, 1943 4 Sheets-Sheet 4113 111 a INVENTOR.

(Rim; AM,

ATTOR/VfVi Patented Mar. 30, 1948 PNEUMATIC TORQUE MACHINE Lewis C.Broecker, Nichols, Conn, assignor to Bridgeport Brass Company,Bridgeport, Conn, a corporation of Connecticut Original applicationFebruary 19, 1943, Serial No. 476,472. Divided and this application June13, 1945, Serial No. 599,181

3 Claims. (Cl. 192-150) The present invention relates to pneumatictorque tightening machines, and more. particularly to a. machine usefulin the assembly of valve-stem parts with inner tubes of tires or thelike, and is a divisioncarved out of my copending application Serial No.476,472, filed February 19, 1943, now Patent Number 2,415,552, issuedFebruary 11, 1947.

In the assembly of valve stems of the detachable type with inner tubesof tires, it has been customary both to assemble the stem parts with thetube and to tighten the parts by hand. This usually has resulted in lackof uniformity in the finished assemblies as well as in frequent damageto the tubes resulting from over-tightening of the valve-stem parts. Itis diflicult to judge the extent of tightening accurately when it isdone by hand. In mass production, uniformly tightened assemblies areessential and the need for means to ensure such uniformity is apparent.

An object of this invention is to provide a novel machine to which theinitially hand-assembled tubes and valve-stem parts may be delivered forthe application to each of the parts in assembly of a final tighteningoperation that will result in uniform tightening of the parts on eachtube. This is accomplished in the machine to be presently described bythe utilization with it of a controlled pressure system which serves tooperate a tightening member in the machine in such a way that it willgive a final tightening to the assembled parts of the valve-stem inconjunction with each tube to exactly the same amount.

Such a control system preferably should be independent of the fluidpressure used therein. It is another object, therefore, of thisinvention to provide novel means in conjunction with such system toeffect this result.

Another object is to provide a machine that is simple to operate and bymeans of which rapid quantitative production may be effected,

Still another object of this invention is the provision of a novel meanswhereby the torque exerted by the tightening member is adjustable to anypredetermined amount.

A further object is the provision of a fluidpressure system foroperating the machine and of electrically-operated controls for saidsystem.

Yet a further object is the provision in the device of signalling meanswhich will serve to Warn the user or operator whenever improperlytightened parts exist in the machine.

Another object is to provide a machine in which the tightened parts maybe aligned uniformly,

2 with respect to the tube or other part on which they are tightened.

To the accomplishment of the foregoing and such other objects as mayhereinafter appear, this invention consists in the novel constructionand arrangement of parts hereinafter to be described and then sought tobe defined in the appended claims, reference being had to theaccompanying drawing forming a part hereof, which shows, merely for thepurpose of illustrative disclosure, preferred embodiments of theinvention, it being expressly understood, however, that changes may bemade in practice within the scope of the appended claims withoutdigressing from the inventive idea.

In the drawing, in which similar reference characters denotecorresponding parts:

Figure 1 is a side elevation of the machine;

Figure 2 is a front elevation of the machine;

Figure 3 is an enlarged fragmentary vertical section taken along theline 33 of Fig. 2, and viewed in the direction of the arrows;

Figure 4 is a section taken along the line 4-4 of Fig. 3 and viewed inthe direction of the arrows;

Figure 5 is a schematic view of the control box used with the machine;

Figure 6 is a diagrammatic view of the pressure system, of componentparts thereof, and of controls therefor;

Figure 7 is an enlarged view of a modified construction equipped foroperating on valve stems equipped with bridge washers;

Figure 8 is a perspective view of a valve stem having a bridge washer;and

Figure 9 is a diagrammatic view of the pressure. system, of componentparts thereof and of modie fied controls therefor for operating themodified construction of Fig.

Referring to the drawing, and first to'Fig. 3, the valve stem is ofconventional construction and comprises two parts, namely, a stemmember, or element I, and a detachable base member 2. The detachablebase member 2 has a threaded part 4. This part 4 is inserted through theusual opening 50f a tire tube 6 from the inside of the latter. Then, thestem member I is screwed onto the outwardly-projecting portion of thebase member 2 and tightened. This clamps a portion of the tube 6 aroundopening 5 between the base member 2 and a flange Id on the stem memberI.

The stem member I has a wrench-engaging portion 1 on its externalsurface. In this embodiment, this portion resembles a hexagonal nut. Itmay, of course, have other suitable to give final tightening to theparts-With uniformtorque, so that the valve-stem parts oneachsuccessivetube when removed from the machine are tightened to a uniform extent. I

The machine for accomplishing this: itself comprises uprights, or framemembers ll), of suitable height extending from a base portion ll. Theseported-from theframe or housing 28 in axial uprights at their upper endsare providedwith laterally-extending bent-over portions Ina. The

latter are adapted to rest on a suitable-table'T' to which they may besuitably secured. A tubularguide member i2 is suitably supported on thebent-over portions Ilia. This guide member slid ably supports a tubularrod or member H5. The

tube or rod l3 at its lower end is suitably coupled to a lever ortreadle [4 by means of acoupling member l5. This coupling member ispivotally secured at 16 to the foot lever M. It is also, secured'to thetube l 3 in such a way thatthe latter may rotate on its longitudinalaxis while it is given"reciprocatory motion on movement of the footlever or'pedal Id. The pedalor lever the'base H of the uprights).Suitable tension- 7 M, in turn, is pivoted at I! to a suitable bearingorsupport It, which latter in turn is carried oning means-sucha's a spring20, is provided. This a ber 25, is fixed tot-he tube member l3 suitablyat 2B. This member 25 is provided with a-suit ably attached cushioningpad- 21 0f rubber'or other equivalent available material for apurpose tobe presently described.

A frame or housing" 28 iscarried suitably by the uprights if), beingsupported therefrom inxany desirable Way, as by the bolts 29. A table orplate member 30 is resiliently supported by and-above the housing 28, asby the slidable pins or bolts 3|,

on which the springs 32 are positionedin such away as to urge the member38 upwardly away from-the frame orhousing 28. Suitable limiting nuts 33threadedly engage the bolts 3|.

A= hollow spindle 35 is carried by the housing 28 in the ball bearings31. A portion 38-of said spindle 35 projects upwardly of the frame or'housing 23. This portion carries a spring 40} thereon. A socket wrenchor other-suitable tight-y ening member 39 of conventional constructionisremovably positioned on the portion.38"of the spindle 35 and rests onspring '40. This socket Wrench is of conventional construction and hasa; wrench portion 4| admeasuredand shapedto receive;v thewrench-engaging portion 1 of: the stem l. The said'wrench..member"'is.slidably key'edfto the'spindleportioni38,as at #2.The in' In this ternal diameter of the hollow spindle 35 is so adsmeasured that the valve steml may be'freely inserted into it through theopen upper end of the portion 38, and through an opening 3M in table 30.

Means are provided to rotate the spindle 35. To this end, the spindle-35carries a pinion 35 which is suitably fixed or keyed as at 43 to thesaid spindle. A rack 48 meshes with the pinion" 45. This rack isslidably supported in asuitable guide bracket '49 Within the housing 28.Roller bearingvEU ispfovided to facilitate free sliding of therackrThenrack iii is adapted to be operated by means-of pneumatic or otherfluid pressure. To thisend, asuitable pressure cylinder 52 issupalignmentwith the rack 48. The cylinder has a piston 53 therein towhich the rack member is coupled as'at 54. The pressure cylinder 52 isprovided with an inlet nozzle 55 to which air, 'or othenfluid; underpressure, maybe delivered. A spiral spring? 56 is carried ion aportion-51 of the spindle 35; Thisspringf has one end 58 attached at 59to a fixed support 60. The inner end of the spring. is attached to.therportion 57 of the spindle in any suitable way. This spring servestotend to return themovable parts associated'with the. spindle 35 tooriginal position upon' removal or. release of pressure in. the cylinder52. Other suitable-return means may be used.

A" control box 10 "is: suitably attached to; the

bent-over portions illa of ,the upri'ghts It. This control box containsthecontrol elements of the? pressure system in acompact manner. Thesecontrol" elements comprise" a solenoid-operated three-Way valve 1 I :ofconventional 7 construction, apressure switch 12 of ,conventionalconstruction,

a main switch-13 of conventional construction;v a solenoid ofconventional construction, and;

the requisite couplings, conduits and electrical wiring necessary;tooperate the pressure system. The solenoid-operated three-way. valve :1I may, for ex-ample, be'one manufactured by the AutomaticswitchCorporation and known as the type P37XAA,-form F. This valve-has aninlet A; .an exhaust outletB, and a deliveryoutlet C. It also has asolenoid 16 for operating it. Normally the valve 'H- is biased by'any-conventionalmeans such as aspring- (not shown) 'or the like,sothat' with the solenoid" de-energized; the inlet A isclosedtorpressure from a supplyline and the passageway' between C, and Bis:open. When; the solenoid 16, isenergized;:the'passagewaybet-ween inlet-Aand deliveryoutlet-Q is opened while the exhaust outlet Bis closed; Thevalve isreturned automatically to thenormal position wherein inlet Aisclosed-to pressure from the supply linethrough the action ofconventional-biasing means when the solenoid-is -de-energi'zeds Anyother suitable solenoid-controlled three-way valve may. be used; thatdescribed being. merely by way of an example. a Y I The pressure'switch"is, also of conventional. construction: Inthe embodiment showniF 6')-it-comprises -a' casingaoi 'I'l'iiscasing' contains a bellows member 3|which has an inlet 82; A plunger member is in engagement with thebellows- 81 and is provided with a suitable elec tr'ica'l contact 84.".l'fhe plunger member and its cbritaict 84 af'e movable toward andawayfrom a stationaryelectrical contact- 85." A suitablespmigi 85 surroundsthe'plungenmember 83-and tends normal ly te' crnlapse' the bellows 84maintaining the ccntants aa anu '85 'apart, or in open circuitj itab e:m'eansa imistratd iagram a coupling member- I2I.

matically by: the. manipuiating i 8.1;. serve; ta This regulation variesregulate the. spring. 86. the inflation pressure necessary: in, thebellows.

8:I to cause engagement between. the contacts-.84:

is released the plunger moves. outwardly: and;

contact 9I movesaway from contact 92, openingthe switch. Anyothersuitable switch may. be used;

The solenoid I4, which is used in conjunction with, and to control, theswitch I3, comprises a solenoid coil 95- and a solenoid plunger: 96a Thelatter is normally urged outwardly of the coil, as by -a spring 91, whenthesolenoid is die-energized,

Switch '53 is suitably positioned in the control box with its plunger 93extending upwardly; The solenoid I4- is positioned in thecontrol boxwith its solenoid arranged out of axial alignmentwith the plunger 93.The solenoid plunger hasayoke member 91' that normally engages a stopmember 98 suitably attached to the casing 90; Thisstop member limits theoutward stroke of said plunger 96. A trip lever 991s pivotally connectedto the yoke member. It hasa part-99a. that extends over the plungermember 93. The lever 99 also extends outwardly of the control box 10'. Asuitable spring 9% serves to so maintain thetrip lever 99 with respectto plunger 93" that switch 13- is normally open.

The parts just described are adapted to beconnectedas follows:

Air, or other fluid under pressure, is delivered from a source (notshown) to the inlet I of an air strainer I9 1 of conventionalconstruction. The outlet I62 of this air strainer-is connected by aconduit I93 to the inlet A ofthe three-way valve I I. The deliveryoutlet C of the three-way valve II is connected by a conduit M4 to thebranch I95 of a suitable coupling member I 06. Anotherbranch lIi'I ofthe coupling member I06 is connected by a conduit I08 to a conventional,

pressure gauge I99 of any known construction.

A third branch III] of the couplingmember N16. is connected by a conduitIII to one branch H 2- of a coupling member H3. Anotherbranch N4 of thecoupling member H3 is connected by a suitable conduit or hose H5 to abranch I20 of A branch [22' of this coupling member I2] is suitablyconnected to the nipple leading to the pressure cylinder 52'. Athird-branch I23 of the coupling member III is fitted with a suitablenormally open, one-way valve I30.

The branches I22, I23 of the coupling member I2I are in axial alignment.A plunger rod |3I extends from the piston 53 through the nipple 55 intoengagement with the valve I30. This rod normally tends to press thevalve [39 onto its seat I32 against the operation of the valve spring!for a purpose to be presently described.

The coupling member I I'3 also has a branch I I9 which is connected by asuitable conduit III to the inlet 82'of the pressure switch bellows 8|.

'Ihe solenoid 16 of. the three-wayvalve lljis connected in electricalseries with the contacts 9|, 92" of the main switch I3; and withthe'conduits..;I 3i, 'Imof power scnrceiii byesuitabie electrical.connecting:members:li ;1 .311 ,i392 switch-control solenoid:9551s.:c0n11e52teri; in series with the-.contactafit. of'thQIiIBSSHIEsSW-itfih; 12:

by the. respective electrical-connecting members I 40; M'Ii and: M2;

Asmentioned. above, the trip lever? ilsnextemis. outwardly oftheecontrol bom as. shown..in.=figs-.. l and ii and extendsintolthetpath ofcan, adjusts. able-tripmember I 43; Thea-trip memberI143 is; adjustably and resiliently-positioned in; amp-suit.-abl'emanneron the pressure pad member 2.5.- In this way; energization'ofthe solenoid:v 11B ,of the three-wayvalv 'IrI ismaderdependent;upon.the? position of the pressuremad member 2 5..

The. operation of the-machine i's'aszfollows In the normal positionoftheparts the pres. sure-pad; member 25 is swung away =fronr over thesocket wrench 39 and the camf 'o'llowen ZZf-is located at the upper-endof -thegroovell -in the: guide- I-2-. At this time, too, the piston-531min the position shownin Fig. 4 that is, at the ex'-. treme right end ofitsstroke. Also, atthis-time, the contacts 9-I and 92 of themain switchare apart, as are-thecontacts-134 85- of=thepressure-switch 12-. Inaddition, the three-wayvalve is closed at its inlet A, so'that', thefluid pres-z sure from the source, entering the airstraiher; I'M, cannotpass tothe system;

With this-static condition of the parts, the operator inserts thesternmember -l of a valvestem intothe spindle- 35 through its upper anduntil the flange Id rests on thesocket-wrench 39: The the tube 6,associated with the valvestem, then restson the table or plate member30; The balance-otthetube overhangs thetabl'e and=issupportedybythe-tuberest- I48.

The operator thendepresses the lever-or foot-- pedal; M' to thefull-line positionshown in Fig. 1'. Thisdraws the rod I3 downwardlyBecauseof the engagement of the-camfollower-22 in-the cam slot-"2|;thepresSure-pad-member 25=swings into alignment over the spindl'e;38,and 'its pad Z'Ipresses or bears downwardly against the; tube 6.Sufiicient counter pressure is developediby the resistance. oftheresiliently-supportedtable 39 and the resilientlyesupported socketwrench 39 to prevent ,anyslipping ofjthe base member? inside the tube6'.

Justat. about the time the pressure pad member. 25; reaches. theaforedescribed" pressing position, the, trip member I43 engages andoperates the. trip.,lever 99;,to, cljosethe switch: 'I3'.. The 010- sureof. switch I3 causes thegsolenoid;1.6;ofi'the three-way valve 1.1 to beenergized This energizationopens inletAof thevalve I'I: tov air, orother. fluid pressure, delivered to strainer IDI, andl .als0.perm itsfree passage oi 'thispressure through. the, delivery outletpC? of the.valve tothi conduit. I94. Exhaust. outletB of the ..va1ve-is;then-closed. From, the.- conduit. L4,. the. pres.- sure isled-.throughtheconduits III, and I I5 and through the coupling; memberI2=I to= the pressure cylinder 52. Atgthe instant when air-pressure:reaches thecouplinzamember Ill-l theyalve; IM ismaintainedromitsseatlay-the: pluncenrod: III, sothatthe cir-pressure.is-..rorcedsto.enterrthe cylinder 32 and to actuate pistonfl; thereby moving the-rack membertoward the left or Fig.4; Suchmovement-of the rackmember- 48; because0111 its-engagementwith theraclr pinion- 48; causesrotationof-=thespindle; Thisrota-- tion impartwa-tighteningmovementtotlie socketwrenchf39'afid thereby tightens the stem mem bef il withrespect'to'the'base'memberi. Th-e pressureconduit' I I'Ibranches from theconduitII I'so that the same pressure existsin saidconduit, an'd in'bellows 8 I, as inthe conduits III and H". This'pressure will'notbesufllcient to actuate the bellows until sufficient "torque, isexerte'd'on' the stempart's. As'the'pist'on moves toward 'th'e1efiT,it'en'coiinters more resistance because" of the increasing "resistanceencountered by the rotating socket "wrench .39 as thelattertight'ensthe' stem parts. I The increasing resistance. to 'motion' orthe: piston 53' builds up .pressure "in the conduit II5iand-in. theconduit II'I, sol-that-ithei pressure in the bellows; increases; Whenthis pressure equals-or exceeds the setting: of the? pressure switch,the bellows expands and-moves to 'close'the circuit of the solenoid I4through the contacts 84 and 85; As soon as this occurs; the"solenoidplunger 96 is drawn into its solenoid '95- against the resistance of itsspring 91. Such movement'of the plunger 96 lifts the trip lever 99sufliciently to permit plunger 93 to riseand'to open the circuit of thesolenoid. at the'switch'13. This immediatelycuts 01f air pressure at'theinlet'A of the thre-way valve I I and permits the pressure system tobleed both pressure at the inletA' of the three-way valve TI and aroundthe exhaust valve I35, which becomes unseated when the air pressuredrops sufficiently for spring 1:33 to open it as the rod I-3I is outof-en agement with it. The operator then- -lifts his-foot from thetreadle I4 and the spring'20 causes the lifting of the clampingorpressure-pad member 2'! from its engagement with-the tube 6-on table'30 and its return to original out-of-t-he-wayposition. The operatorthen removes the tube and its tightened valvestem partsfrom the machine.Since the bleeding just described,- can.,take place,1the spira-l spring56 then acts to restore the piston 53 and rack 48 to the conditionshownin Fig 4. Initialconditionsare then restored in the entire machineandthe samesequence of operations are carried out on the next tube andValve-stem assembly-.;'-- V 7 '-It will be seen th'at,with the machineand the pressure systemjust described, the amount of tightening torque.exerted by the socket wrench 39 will always be equal for any givensetting of the pressure switch .'I.2,-regardless' of theair pressuredeliveredtothelstrainer Iill, providing that the latter-pressure isalways greater, than that necessary to give thefldesired torque at thesocket Wrench '39.- .This is true because thejprejssure switch.'l2then.always. closes on the existence of:

a determined pressure in the bellows 8I'. That determined pressureoccurs, ,each time the socket .wrench encounters a specific resistingforce inits tightening action on the valve-"stem parts In efiect,...ther.efore, the pressurejavailableto operate the piston 53 isdetermined by the setting of thepressure switch l2, irre spec'- tive ofthe pressure-of the sourcefprovi'ded'the latter is higher; The settingcan be changed."

l f 'thel valve parts have been insufiiciently tightened before they areinserted intd the ma-r ch'inegthe limited movementiavailableito the rackme'mbera48 .will .beiinsumcient to cause the necessaryfinal-tightening;As a result, the/rack mem -i her-will .tend to 0,v ertravel, i, e.-,movemore-than is; connected in any suitable waygin an electrical;

circuit; "including a; signal "lamp orbell 141; The r signal;e.'"g'.;lighting6f the lamp'or' ringing'of thefbell', at any time:during the operationfof the sides of the tube. :Usingthe machinedescribed above, VeryfeW stemswouldthave their--Bridge washers properlyaligned with air cut-off occur: ring when the required torque ,has beenapplied.

It becomes necessary therefore to-provide additional means for rotatingthe stem Ia; its base 2a and Bridge washer relative to the tube afterthe requiredftightening torque has been applied to align the Bridgewasher? properly with'respect tothetube." t 1 This may beaccomplished-simply by the additional mechanism and circuit connectionsshown in Figs-7 and 9 without-requiring any changes-in other structuraldetails of themachine hereinbeforedescribed. r

"Fig; 7 is a top plan view-ofthe sprlng pad or table 35 of Fig. 3 and anend view' of the valve stem- Ia with it attached Bridge washer-:Ib.

The-stemis shown inserted into-the socket'wrench' ready fortighteningonto an inner tube but the:

latter is omitted for clarity; j r

Suitably attached tothe underside a; springpad 30 are a solenoid I 50,2. switch I 55. (similar in construction to switch-13) and a switchoperating lever I58. The armature [5| of theiso1enoid150- ispivotally'connected at I52 to a link I53. -The latter is pivotallyconnected at; I54 tothe operating lever I58. rThe lever 158 at itsopposite end is slotted at I59.- A'pin' IGD depending from the pad35extends through said slot serving both to support and to guide the lever-I 58 at this opposite end. 1- A suitable tension "spring ;I6I; attachedto said lever at I6 2and to a pad 30 at I63 serves normally to maintainthe lever I58 in the dotted line position of Fig. 7, i. e., with the pinI 6!] in engagement with the left hand-end of slot I59. A projection I64 provided on-lever I58 is at this time spaced from theoperating-plunger I56 of the switch 55 so that the contacts -I 51, I58of the latter are separated or in open position.

The leVer' I58 has another projectionor pin: I 66 which is'pos-itionedto lie clear of the Bridge washerfllb when lever I58 lies in;thedottedline position of Fig. '7,

When the solenoid I50 is actuated 'as will be presently described'thelever I53 is swung-by the linkage I53 to bring the projection or pins-Iint o the path oi movement of a flange lc of the Bridge washer Ib andwhen the two engage,

furthermovement ofsuch flange 'moves the lever I58Jtoward the left ofFig. 17, bringing projection I54 into engagement with the switch plungerI56 to close the;.. swith: I55." The admeasurement of lever" B 58and-the position of .itsprojection fli l,

. are such that. switch I 5.511s .closedfwhen the Bridge; washerLassumes the position show-n fin. Fig. I at which timelitisproperlyaligne'dTwith the tube. g Atthis time the-lever I58-is inthe'dotdashline positionfshovvnin Fig.3. 11 W l solenoid-I50 andlswitchll55 arecantata acemes '19 with the other parts of FFigfiG' in the mannerillustrated' in Fig; 8 wherein all partshavin-g' reference numerals likethose :of' Fig. '6 :arevsi-milar.

The solenoid 160i the three-wayyalve '='II is connected in "electricalseries with the-contacts 9|, 92 of the main switchz'l3 andwith the con-'duits "I35, I36 ofthe power source? by suitable electrical connectingmembers or wirin'g's I 31, 138, I39. The control'zsolenoid 950i theswitch 13 is connected in electrical series with the contacts I51, "I 58of the switch I55"(can'ied by Spring plate 39) and the conduitszI-35,1.36 of the lpowerisource P by the respective electrical connectingmembers or wirings I19, III, I12, H3. The contacts 84, 85

of the pressure switch-12 are'connected in electrical series withthesolenoid I59 (carried by the spring pad or table 30) and withtheconduits I35, I 36 by the respective electrical connecting members orwirings I14, I'I5,-I'I6 and 173,

In operation, assume that a stem I a equipped with a Bridge washerassembled-witha tube has been inserted into the socket wrench 39 an'dthe operator has depressed foot lever I4 so that machine parts occupythe positionsshown in Fig.3.

At .this time the trip member M3 engagesand operates the trip lever 99to close the contacts 9|, 92 of the main switch I3. This closureenergizes the solenoid I6 of the three-way valve II. This energizationopens inlet A of the valve II to pressure delivered to strainer IUI andpermits free passage of this pressure through outlet C of the valve toconduit I94. Exhaust outlet B of the valve II is then closed. Fromconduit I94, the pressure is led through the conduits III and H andthrough the coupling member I2 I to the pressure cylinder 52 causingrack member 48 to be operated as previously described and consequentlyrotating spindle 35 and imparting tightening rotation to the socketwrench 39 in the direction of the arrow shown in Fig. 7, therebytightening the stem member Ia with respect to its base member 2a.

The same pressure exists in conduit III and in bellows BI as previouslydescribed. As the piston 52 encounters increasing resistance during thetightening action, the pressure built up in bellows 8| ultimately closesthe circuit through contacts 84, 85, thereby energizing the solenoid I59(carried by table 30). As soon as this occurs, the armature I5l of thesaid solenoid moves the lever I58 to bring its projection I66 into thepath of rotation of a flange Ic of the Bridge washer II) which is stillcapable of rotation with respect to the tube under action of the socketwrench 39. The tube is held against rotation by the pressure pad 21.When the flange I0 and the projection I 66 engage, the lever I58 ismoved to the left of Fig. '7, bringingprojection I 64 into engagementwith plunger I56 of the switch I59 carried by the table 30. Suchengagement closes the circuit through contacts I51, I53 of the latterswitch and the solenoid I4. As soon as this occurs, the solenoidplunger96 is drawn into its solenoid 95 against the resistance of spring 9?.Such movement lifts the trip lever 9c sufiiciently to permit plunger 93to rise and to open the circuit of valve solenoid I6 at the main switch13. This immediately cuts oil pressure at the inlet A of the valve IIand permits the pressure system to bleed as previously describedstopping rotation of the socket wrench 39. This rotation stops just whenthe Bridge washer Ib becomes properly aligned as shown in Fig. 7. Atthis time proper tightening torque -alsohas been applied to'the stemparts "Ia, 2a

with :respect-tothe tube. Y

The operator-then lifts his foot from the treadle I4, removes the tubeand its tightened aligned valve stem parts from the machineand thewrench -39 and associated parts return to their initial positions aspreviously described and as shown in -Figs. 4, 7 and 8. Initialconditions thenexist and the same sequence of operations can be carriedout on the next tube and valvestem assembly. While the machine has beendescribed as particulairly efiective in connection with the tight--ening of valve-stem parts and tubes, it should be understood that ithas application to the tightening 'of :other parts, wherein a final,uniform tightening torque is necessary. I

it is to bexunder'sto'od, too, that structuralvariation within the scopeof the appended claims is contem plated. There is no intention-oflimitationto' the exact details shown What is claim'e'd is:

'1. In a fluidpressure-actuated device for uniformly tightening partstogether on another part, means for delivering "actuating fluid underpressure to said device, valve means in conjunction withsaid'fluid-delivering means, electrical means for operating said valvemeans, said electrical means including a solenoid for operating saidvalve and a switch for connecting said solenoid to a source ofelectrical power, a second solenoid, pressure-responsive electricalcontrol means for connecting said second solenoid to said source ofpower, a movable member operated by said second solenoid and movable inresponse to the position of an element of one of said first-named parts,a second switch responsive to movement of said movable member, a thirdsolenoid connected to said second switch and to said source of power andmeans coupling said third solenoid to said first-named switch to openand close the latter whereby said valve means will be actuated to outoff said fluid under pressure when a determined amount of tighteningaction has been effected by said device and said element has been movedto a determined position.

2. In a pressure-actuated device for uniformly and described.

tightening threaded valve stem parts together on a tire tube or thelike, a pressure circuit for delivering actuating fluid under pressureto said device, valve means in said pressure circuit to close and opensaid circuit to pressure and means for controlling said valve means,said controlling a means including solenoid means for operating saidvalve to open said circuit to pressure, an electrical circuit forconnecting said solenoid means to a source of electric power, a normallyopen switch in said electrical circuit, means for closing said switch toenergize said solenoid and thereby to open said valve means to admitfluid under pressure to said device, a second solenoid, an electriccircuit connecting said second solonoid to said source of power, anormally open pressure-responsive switch in said second circuit, saidlast-named switch being responsive to pressure in said pressure circuitand adapted to close said second electrical circuit and to energize thesaid second solenoid at a predetermined pressure in said pressurecircuit, and movable means operated by the energization of said secondsolenoid and serving to open said first-named switch thereby tode-energize said first-named solenoid means and to permit said valvemeans to close said pressure circuit to pressure.

" 3'. "m a pressure-actuated device for uniformly tightening threadedvalve-stem parts together on a tire tube or the like, a pressure circuitfor delivering actuating fluid under pressure to said device, valvemeans in said pressure circuit to I close-and open said circuit topressure and means for controlling said valve means, said controllingmeans including solenoid means to open said valve to admit pressuretosaid circuit, an electrical circuit for connecting said solenoid meansto a source of electric power, a normally open switch in said electricalcircuit, means for closing said switch to energize said solenoid andthereby to open said valve, a second solenoid, a second electriccircuit; connecting said second solenoid to said source of power, anormally open switch in said second circuit, a third solenoid, a thirdelectric circuit connecting said third solenoid to said source of power,a normally open,

pressure-responsive switch in said third electricv 20 Number 'noid'intoa position to be engaged by an element of one of said threaded partswhen'said element achieves a predetermined position during action ofsaid device, and means in conjunction with said movable means forclosing the normally open switch in said second circuit thereby toenergize said second solenoid, and movable means operated by theenergization of said second solenoid and serving to open saidfirst-named switch thereby to de-energize said first-named solenoidmeans and to permit said valve means to close oif said pressure circuitto pressure.

LEWIS C. BROECKER.

REFERENCES CITED The following references are of record in the file ofthis'patent:

UNITED STATES PATENTS Name Date 2,028,379 Davis Jan. 21, 1936 2,068,745Hall Jan. 26, 1937 2,139,064 Beattie Dec, 6, 1938 2,156,118 KliesrathApr. 25, 1939 2,258,068

Ra'ndol Oct, 7, 1941 Certificate of Correction Patent No. 2,438,692.March 30, 1948;

LEWIS C. BROEGKER It is hereby certified that errors appear in theprinted specification of the above numbered patent requiring correctionas follows: Column 4, line 41, for neecssary read necessary; column 7,line 26, for thre-way read three-way; line 28, for pressure at the inletA read through the outlet B; and that the said Letters Patent should beread with these corrections therein that the same may conform to therecord of the case in the Patent Oifice.

Signed and sealed this 25th day of May, A. D. 1948.

THOMAS F.- MURPHY,

Assistant UMI/mz'ssz'oner of Patents.

